Technical Modify Fuel Bowl

Hey Boys I have a 4165 Holley 800 Spread Bore. It is a double pumper with end hung float bowls.
I want to put center hung bowls on it but don't have a secondary bowl for a double pumper.
Anybody here ever modify a rear vac sec fuel bowl to double pumper like I need?
A forum member sent me a pair of fuel bowls last month for another carb-Thanks!- and looking at one them all it looks like is I need to drill a hole in the pump cavity. The delivery hole was already there. The newer carbs have those rubber umbrella check valves & I don't think I would need to have that cross bar installed that held the Check Ball Valve in like the older ones. I think I can drill the hole & install an umbrella valve & it should work. Well I think I need to drill TWO Holes, suction & discharge.
I found some bowls like I need on ebay but damn I spend too much money on this stuff & I just bought a $10 Vac Sec 3310 dual feed with the base plate rusted together for parts yesterday with this swap in mind & want to use these bowls if possible.
Thanks!

 

Yes I've put center hung flute bowls on the vacuum secondary carbs, they come on the 750 vacuum secondary carbs. Holley sells a kit for doing such things...

 

Before you get too far into this, somewhere in the back of my brain I seem to remember that the only bowls that work on that carb are 4165/4175 series. I remember watching for the 800 cfm models to get the center hung bowls for my list 6210 650 cfm carb.
This seems to back this up-https://www.holley.com/products/fuel_systems/carburetor_components/floats_fuel_bowls_and_components/fuel_bowl_kits_and_components/parts/134-104

 

Man they snuck that in on me! Looks like a call to Holley is in order here!
Anyway what I wanted to do won't work with the rubber ck valve, the cavity with the ck ball is not made right for the rubber valve. However the steel ball ck will work after holes are drilled.
I've not removed any bowls from this carb yet, I'll do that this week & compare & call Holley as well. Man sometimes I think in the world of stuff to know I know just enough to stay in trouble all the time!
Thanks for the help riverview!

 

OK here's what Holley had to say. There's no reason why the fuel bowl won't bolt on & work. But the reason they exempt the 4165 is because it is a transfer tube carb & if a person just bought a secondary or primary carb then it wouldn't all be compatible. Duh...Second is the carb was made to use the OEM fuel delivery line from the fuel pump & that aint gonna work no more with center pivot bowls. Again, Duh...
Stay Tuned!